The Reds got right-hander Todd Redmond from Atlanta for shortstop Paul Janish in a swap of minor leaguers on Saturday.
Redmond went 6-6 with a 3.58 ERA in 18 starts for Triple-A Gwinnett this season. The 27-year-old pitcher was assigned to Triple-A Louisville.
General manager Walt Jocketty said the trade gives the Reds some pitching depth in the minors. The Reds have used only five starters through the first 87 games this season, a franchise record.
The pitching staff has kept the Reds in contention in the NL Central. The staff ERA of 3.39 was Cincinnati's best at the All-Star break since 1990.
Janish, 29, batted .237 in 49 games at Louisville. He played in 324 games for the Reds from 2008-11, batting .221 with seven homers and 70 RBIs.